The invention relates to improvements in apparatus for damping vibrations between the driving and driven (primary and secondary) components of power trains. More particularly, the invention relates to improvements in apparatus which can be utilized to damp vibrations between the rotary output elements of engines and rotary input elements of transmissions in motor vehicles.
Vibration damping apparatus of the above outlined character normally comprise a first or primary flywheel which is connectable to the output element (e.g., a crankshaft) of an internal combustion engine, a second or secondary flywheel which is coaxial with and is rotatable relative to the first flywheel and is connectable to the rotary input element of a variable speed transmission, and means for transmitting torque between the flywheels. Certain presently preferred torque transmitting means include a torsionally elastic damper in series with a slip clutch which employs a flange-like torque transmitting device. The flange-like device is stressed in the axial direction of the flywheels and transmits torque from the damper to the slip clutch.
It is also known to provide one of the flywheels with a chamber which is at least partially filled with a viscous fluid and serves to receive a portion of the torque transmitting means. The means for stressing the flange-like torque transmitting device is carried by the other flywheel, and the other flywheel can transmit torque to the input element of the transmission by way of an engageable friction clutch. Such design ensures that friction heat which is generated during engagement or disengagement of the friction clutch is less likely to affect the condition of the confined viscous fluid and the operation of those parts of the torque transmitting means which are confined in the aforementioned chamber of the one flywheel.
Vibration damping apparatus of the afore-described character are described, for example, in German patent application No. 39 09 892 of Johann Jackel (published Oct. 12, 1989). Such apparatus exhibit a number of desirable advantages. However, the cost of presently known vibration damping apparatus is relatively high, primarily (or to a large extent) because the assembly of their parts constitutes a complex and time-consuming procedure.